Some important events in the history of Onsala Space Observatory

1949: Onsala Space Observatory is founded by professor Olof Rydbeck.

1950: Interferometer observations in Onsala of radio waves from the Sun and the Galaxy.

1955: Hydrogen in the spiral arms of the Galaxy is observed from Onsala. The observatory is inaugurated. Research and education is now conducted in radio and radar astronomy, space physics, and radio communication.

1963: The 25.6 m radio telescope in Onsala is completed. During the first three years, the telescope is used not only for radio astronomy, but also for experiments with satellite communications.

1967: A very sensitive receiver (of maser type) developed at Chalmers is mounted on the 25.6 m telescope, which becomes the world's most sensitive telescope of its kind.

1973: All three spectral lines at 9 cm wavelength from the CH molecule are discovered with the 25.6 m telescope. Subsequently, the large scale structure of the Galaxy is studied using observations of CH.

1976: The 20 m radio telescope in Onsala is completed and inaugurated by King Carl XVI Gustaf. The telescope is, for almost ten years, the largest millimetre wave telescope in the world.

1979: A spectral line survey at 72-91 GHz towards Orion A (a star forming region) and IRC+10216 (a carbon star with a dust shell) is started with the 20 m telescope. Many new spectral lines from more than 20 different molecules are discovered in the survey.

1987: SEST (Sweden-ESO Submillimetre Telescope) is completed. This 15 m diameter millimetre and submillimetre wave telescope is situated at 2400 m altitude at the ESO (European Southern Observatory) site on the mountain La Silla in Chile.

1988: Observations with the 20 m telescope show that the molecular gas follows the optical spiral arms in galaxies like M 51. Using VLBI, the nucleus of the quasar 3C273 is observed with an angular resolution of 50 microarcseconds.

1990: Onsala Space Observatory becomes the Swedish National Facility for Radio Astronomy. Using SEST, chemical properties of the Large Magellanic Cloud are studied and eight new molecules are discovered.

1992: A spectral survey (225-250 GHz) of the centre of the Galaxy made with SEST is completed and many molecules are identified.

1997: Several molecules, including HCN, are observed in comet Hale-Bopp.

2001: The astronomy-aeronomy satellite Odin is launched into Earth orbit. Odin is a cooperation between Sweden, Finland, France and Canada. Important parts of the submillimetre receiver system were built by engineers at the observatory.

2004: The first e-VLBI experiment took place between Onsala Space Observatory and radio telescopes in Westerbork, Holland, and Cambridge, England.

2005: APEX, the Atacama Pathfinder Experiment, a 12 m diameter submillimetre wave telescope for frequencies up to 1500 GHz is inaugurated. Located at the high altitude of 5050 m in the Atacama Desert in northern Chile, APEX is a collaboration between Onsala Space Observatory, Max Planck Institut für Radioastronomie (Germany) and European Southern Observatory. Professor Hans Olofsson becomes Director of Onsala Space Observatory.

2006: The results from the first observing season with APEX are published in a special issue of Astronomy & Astrophysics. Many observing projects are related to star formation and use a receiver built by the observatory's receiver group.

2007: The first detection of oxygen molecules in a cosmic gas cloud, made with the Odin satellite, are published. Successful e-VLBI (real-time electronic VLBI) observations are made: for the first time, data from six telescopes (including Onsala) are transferred in real time at 512 Mbps to a processor in the Netherland, which quickly produces a radio map.

2009: The International Year of Astronomy 2009 is celebrated in different ways, e.g., with a public event at Universeum showing the launch of the Herschel telescope. A superconducting gravimeter is installed at the observatory.

2010: The geoscience activities become an official part of the observatory's mission, according to a new contract with the Swedish Research Council.

2011: The LOFAR station is inaugurated by Minister of Education Jan Björklund.

2012: VLBI observations with APEX, SMA (Hawaii) and SMT (Arizona) resulted in the highest angular resolution ever in an astronomical observation: 28 microarcseconds. Onsala Space Observatory, representing Sweden, was formally accepted as the ninth member of the international consortium which will design the Square Kilometre Array (SKA).

2013: Professor John Conway takes over the position as director of Onsala Space Observatory after Hans Olofsson. LOFAR is used to image supernova remnants in the starburst galaxy M82.

2014: The radome protecting the 20 m telescope is replaced.

2015: The tide gauge station is inaugurated by Rolf Brennerfelt, the Director General of the Swedish Meteorological and Hydrological Institute (SMHI), and Mats Viberg, the Vice President of Chalmers. The station is thereafter included in SMHI’s national network for sea level observations.

2017: Onsala Twin Telescopes (OTT) for geodesy are inaugurated by Lena Sommestad, county governor in Hallands län, and Lisbeth Schultze, deputy county governor in Västra Götaland.